diff --git a/src/bin/day21.rs b/src/bin/day21.rs
index 814c338..d591841 100644
--- a/src/bin/day21.rs
+++ b/src/bin/day21.rs
@@ -108,4 +108,4 @@ fn main() -> Result<()> {
     Day21::main()
 }
 
-test_sample!(day_21, Day21, 0, 0);
+test_sample!(day_21, Day21, 0, 0.0);